John b



(No Model.)

J. B. GORNWALL.

SIEVE.'

Patented June 18, 1889.

u Us QJ MII. am

UNITED STATES l PATENT OFFICE.

JOHN B. OORNVALL, OF MOLINE, ILLINOIS, ASSIGNOR TO THE BARNARD t LEASMANUFACTURING COMPANY, OF SAME PLACE.

SIEVE.

SPECIFICATION forming part of Letters Patent No. 405,660, dated J une18, 1889.4 Application filed May 9, 1888. Serial No. 273,316. (Nomodel.)

To all whom t may concern.'

Be it known that I, JOHN B. CORNWALL, of Moline, in the county of RockIsland and State of Illinois, have invented certain new and usefulImprovements in Sieves; andI do hereby declare that the following` is afull,

clear, and exact Idescription thereof, reference being' had to theaccompanying drawings, and to the letters of reference marked 1othereon,which form part of this specification,

in which` Figure l is a top plan view of my improved sieve. Fig. 2 is avertical cross-sectional view of the same on line :t .'12, Fig. l. Fig.3 is a section on line g/ y, Fig. 2. Figs. at and 5 are detailsillustrating modifications of the form of the teeth and slots of thestrips O. i. Fig. 6 is a detail sectional View.

This invention is an improvem entin screens 2o or sieves; and its objectis to provide a screen that will more effectually separate pieces of coband other impurities from corn, will more thoroughly clean other grainand seeds,which will not choke, and which will lthoroughly scatter thegrain passing over it.

To these ends the invention consists in the novel construction andarrangement of parts hereinafter described, illustrated in the drawings,and particularly specified in the appended claim.

My sieve is made up of a number of toothed strips secured to a propercarrying-frame in stepped tiers, and the frame is preferably inclined sothat the horizontal toothed edge of one strip projects over the plainedge of thc adjoining lower strip. The teeth of these strips are taperedoutwardly and the slots or serrations between the teeth are taperedinwardly, so that the spaces between the teeth are narrower at base thanat the extremities of the teeth, as shown, and the toothed edge of onestrip is made to project over the plain ed ge-of the next lower stripjust far enough to cause the coarse impurities passing through the slotsof the strip to fall upon the lower strip,while the clean grain can passthrough the slots with out being caught by the lower strip. The stripsare far enough apart to allow impurities projecting part way through theslots to pass 5 o freely olf onto the lower plate. No impurities canpass through vthe slots until they pass down to where the slots widensufficiently to let them pass or to the ends of the slots, and the plainedge of the lower strip is adj usted just to the point where it will besure to 5 5 catch suchimpurities and allow clean grain only to passthrough the screen. If the plain or upturned edge of the lower strip layclose to the toothed edge of the upper strip it would prevent the escapeof impurities pro- 6o j ecting partly through the slots, thereby chokingthe sieve; therefore I arranged the sieve in stepped tiers, as shown.The plain edges of the strips are preferably upturned or flanged, orhave small strips attached, so that grain would be compelled to pass toand over the toothed edge in order to escape from the strip.

From the foregoing it will be understood that unless the material on thescreen can 7o pass between t-he teeth of a strip it will escape over thetoothed edge of the strips onto the next lower strip, and so pass theentire length of the screen without escaping therethrough. The slotsbetween the teeth have, preferably,divergin g sides, so that the mouthsof the slotsare wider than the inner ends thereof.

It will be seen that by varying the amount of overlapping of the'stripsthe size of the 8o screen openings can be' regulated-in other words, theplain edge of one strip in connection with the toothed edge of anotherstrip constitute the screen-openin gs, although from the verticaldistance between `them it does not prevent impurities from passing offun! obstructed from the slots.

Referring to the drawings by letter, A designates a portion of ascreen-shoe, having inclined guides ct d on its sides. 9o

B designates a frame itting in guides a a. and composed of end pieces Z7Y la and side pieces B', which are formed on their upper edges with aseries of shoulders b', which are of such pitch that when the frame isin its guides the upper faces of said shoulders will be abouthorizontal.

C C are plates or strips of suitable material, preferably of metal,secured transversely of frame B to the side pieces B on the shouldersroo thereof. The said plates overlap, as shown, without impi'nging, andthe overlapping edge of each plate is toothed, the slots c c between theteeth extending rearward beyond the rear edge of the adjoining lowerstrip, shown. The plain or rear edges c of strips C are upturned, asshown, or beaded or otherwise formed to prevent escape of materialrearward and to direct the currents of air upward bet-Ween the strips.

D is a transverse plate at the head of the screen to receive and deliverthe material to the strips, its inner edge d being bent down close tothe rear edge of the uppermost strip C.

E is a plate at the foot of the screen, receiving material from laststrip C, and havingits rear edge e upturned.

The sides of slots c c may be parallel; but preferably diverge towardthe front edge of the strips, in the manner shown in Figs. l, 4, and 5,or in other desired manner. The amount of overlapping of the stripsregulates the size of the screen-openings, as before stated. The slots@being open at front, should any grain or trash catch in the slot, butbe too large to pass through without impinging on the strips C nextbelow, the vibrations of the screen will shift such trash forward andout of the mouth of the screen, where it will be caught by the lowerstrip and shifted from thence to the next lower strip, and so on down tothe lowermost strip, whence it is thrown on plate E, the upturned edge eof the latter plate partially closing the slots in the lowermost strip.The rear upturned edges of strips C impinge against the material on thestrips as the screen is vibrated and drive the material forward over thetoothed edges, thus aiding in clearing the screen. The diverging sidesof the slots also facilitate the escape of material therefrom. Thestrips C can be applied to any screen-shoe in which the motion of shakeof the shoe is in line .with the How of grain.

As the side of the screen-openings can be varied by varying the relativepositions of the strips, it is obvious that the same size of strips canbe employed in making screens for different-sized grain or material.

F is a bar similar to the pieces B and secured to the end pieces b andbracing the strips C. l

G is a screw-threaded stud attached to the head end of frame B andpassing through the head-board of shoe A, Where it is engaged by a nutg, to keep the frame in position.

Having described my invention, I claim- The combination of the shoe andthe inclined frame having shouldered side bars se# cured therein withthe sieve composed of strips C, arranged in a stepped tier on said bars,overlapping but not touching each other and having their rear edgescurved upward and forward and provided with slots in their outer edgeshaving outwardly-diverging sides, all substantially as and forl thepurpose speciiied.

In testimony that I claim the foregoing as my own I affix my signaturein presence o two witnesses.

y JOHN B. CORNVALL.

Iitnessesz E. H. SEIFFRT, CHAs. S. KERNs.

